JSFiddle - React, Tailwind, and code Playground

HTML

<div id='content'>
    <div id='first'>...</div>
    <div id='second'>...</div>
</div>

CSS

html, body {
    margin:0; padding:0
}
div {
    border:1px solid red
}
#content {
    width:100%;
    position:relative;
    padding:20px
}
#first {
    width:70%;
    position:relative
}
#second {
    width:70%;
    position:fixed
}